Various types of seat belt systems are known for restraining an occupant in an automobile, aircraft, or other vehicle. Conventional seat belt systems for cars, trucks and other road vehicles typically include an elongate web forming a lap belt and a shoulder belt. The web typically carries a connector that can slide between the lap and shoulder belts and be releasably attached to a buckle anchored to the floor of the vehicle on one side of the seat base. The opposite end of the shoulder belt typically passes through an upper D-ring or guide and then attaches to a retractor fixed to a sidewall of the vehicle on the opposite side of the seat. The opposite end of the lap belt is typically anchored to the floor of the vehicle across from the buckle.
The retractor can include a spring-loaded reel or spool that retracts the web and takes up slack in the shoulder and lap belts once they have been attached to the buckle. Although conventional retractors allow the web to pay out as the seat occupant moves around, because they are spring-loaded they still maintain a certain amount of tension in, for example, the shoulder belt during use. This tension results in pressure on the neck and/or chest of the occupant that may cause some discomfort, especially during long trips.